According to MTA.me, Chen’s blog, the illustration works in real time and spawns trains that departed in the last minute, and it continues accelerating through a 24-hour loop. The subway trains trigger the visual performance, and intersecting paths generate the music. However, the illustration does not follow the subway system exactly. Chen had to fade out routes and include eliminated subway lines during midnight hours for aesthetic, musical and technical reasons.

Also, below is a video of Massimo Vignelli discussing his 1972 map. The clip is from Gary Hustwit’s documentary, “Helvetica.” Hustwit is now working on a third installment of his documentary film series about design, “Urbanized,” where he will highlight the elements of design that make our cities.